1. Field of the Invention
This invention relates to a ceramic base for a semiconductor device, and more particularly, to such a ceramic base in which the generation of cracks can be prevented.
2. Description of the Related Art
A ceramic base used for mounting thereon a semiconductor chip or a similar electronic element is made of ceramic.
As is well known in the prior art, ceramic generally has a high compression stress resistance, and a low tension resistance.
In a process for manufacturing semiconductor devices, a plurality of such ceramic bases are stored in a storage or accommodation station, and picked up therefrom one by one and fed to the various work stations, such as a semiconductor chip mount station. In the accommodation station, the ceramic bases are guided by a suitable guide means, such as a rail, and fed in the forward direction. To smoothly feed these ceramic bases along the rail, it is usually necessary to provide gaps between side edges of the ceramic bases and side walls of the rail, and due to such gaps, the ceramic bases might slew transversely while being fed along the rail and come into touch with an adjacent ceramic base. This sometimes causes the generation of cracks or flaws in the ceramic base, particularly at corners or edge portions of the ceramic base. Also, a part of the ceramic base is sometimes broken, i.e., edges of the ceramic base are sometimes nicked.
To prevent the generation of such cracks or flaws, as shown in FIG. 12, it is well known in the prior art for a rectangular ceramic base to be provided with bevel portions B at the respective corners of the ceramic base, to avoid a possible concentration of stress when an external force is exerted on the ceramic base.
In general, these bevel portions B effectively prevent the ceramic base form being broken at the corner portions, but do not completely avoid the generation of cracks or flaws in the ceramic base.